Cannabis Abstinence in Bipolar Disorder

The objective of this study is to assess the changes in symptoms and cognition that occur after a 28-day abstinence period in patients with comorbid Cannabis Use Disorder (CUD) and Bipolar (Type I or II) disorder. Stabilized bipolar patients (N=52) with CUD will be randomly assigned to one of two groups: 1) A contingent reinforcement (CR) group (n=26); 2) a non-contingent reinforcement (NCR) group (n=26). The study will include a total of 8 visits to the CAMH Russell site (screening, training, baselines, week 1-4, follow-up). Participants should be between the ages of 18-60, meet criteria for CUD (moderate to severe), meet criteria for Bipolar Disorder, be on a stable dose of mood stabilizing medication(s), and be non-treatment seeking cannabis user. The visits will take up a total of approximately 22.5 hours with compensation for time provided for both groups. These visits will involve multiple clinical, substance use, and cognitive assessments. Abstinence will be maintained by weekly behavioural coaching sessions and contingency reinforcement for the CR group.